What most people don’t know is that the majority of wireless networks provided by U-Verse, cable, etc companies are mostly using the same channel. It means your network will work slowly if at all. This is a great tool for finding how many wireless networks might be interfering, or for finding a hot spot quickly. check it out!
I’ve used inSSIDER along with Vistumbler, but my favorite for now is netstumbler. Oh, and if you want to make a heat-map of your wi-fi network, try out Ekahau HeatMapper (though so far it only works on 32-bit).